Fuse plug



Patented Sept. 5i, 1922.

j UNIT stares REU'BEN B. BNJ'AMN, OFM/CHICAGO, ILLNOS, ASSEGNOR T'BENJAMN ELECTRIM?` MANUFACTURING COMPANY, 0F CHICAGQ,

ILLNIS.

.Y ortica.

ELLNOS, A. GORPGRTION UF FUSE PLUG?.

Applicationy tiled June 2, 1919. Serial No.. 301,265.

. To all fwzgom zz? may concern Be it known that l, REUBEN B. BENJAMIN,

va citizen of the United States, residing at companying drawing, forminga part of this f speciication.

The present invention relates generally to fuse plugs for electriccircuits, and more particularly to fuse plugs in which the fuse` may beviewed through a transparent member and in which the fuse element isrenewable.

One of the'objects of my invention is to provide an improved fuse plugwhich is proT vided with indicating means for indicating when a fuse isblown, the indicating means being renewable so that a new indicatingmeans can be provided each time a fuse is blown.

Another object of my invention is to provide an improved fuse plugprovided with a renewed fuse and a renewable indicating means in whichthe fuse and indicating means are coinbinedvin a unitary device, whichunitary device can be removed when the fuse is blown and replaced by anew device having a fuse and indicating means.

Another object of the invention is to provide a fuse plug of this classwhich shall be simple in construction, durable 4and efficient inoperation, and economical to manufacture. y The various features andadvantages 01; the invention will be more fully understood uponreferring tothe following description taken in connection'pwith theaccompanying. drawing, while the scope ofv the invention will beparticularly pointed outin the appended claims.

In' said drawing, y

Fig. 1 isv a plan view of a fuse plug con structed in accordance withthe present invention; Fig. 2 is a bottom plan view able element of theplug;

Fig. 3 is a vertical section 'of the renewable element taken on a planeindicated by the line 3-8 of Fig. 2;

of the renew-l F ig. 4c is a vertical section of the complete structuretaken on a by the line 1i*4 of Fig. 1;

F ig. 5 is a plan view of the insulating body with the center contactconnecting stripfin position;

Fig. 6 is a bottom plan view of the complete plug; l

Fig. 7 is a perspective view of the upper portion of one element oftheshell member as it appears before being assembled with the other partsof that member;

Fig. 8 is a vertical section 1or a portion of the plug taken on a line 88 of Fig. 1; and

Fig. 9 is a perspective view of one of the spring clipsl by which theshell member is secured to the insulating body. Throughoutv these viewslike characters refer to like parts.A i

Referring to the drawing in detail, the main plug member A includes theinsulating body 10 and the connecting strip 11 which terminatesat oneend in a center contact 12 and at the other end in a Vfuse engagingportion 13.; B designates thej renewable fuse element and C designatesthe shell` member which holds the fuse element in place and provides theshell contact 14 of the plug.

The insulating body 10 may be composed of any suitable insulatingmaterial. Ordinarily porcelain will be used for this purpose andthe bodywill be molded in the,

Vstrip shoved upward until the end13 slips over the end of the wall 15and finally rests in the recess 21 formed forV it in the wall. When thestrip has been put in this position it bears near its center against oneside of the partition 16, at its upper end against plane indicated bytheplane indicated l the wall 15, and at its lower end against the side otthe opening 19. The lower end of the strip is given an angular turn 22which causes the lower end et the strip to tit snugly over projectingportion 23 on the lower tace oi the insulating member l0. ln this way,the end ot the conducting strip 11 forms the center contact 12 of 'theplug and the upper eud provides the bearing and contact face 13.

The removable 'fuse and indicatingl element B comprises an insulatingmember 24 which is provided with an elongated central opening, 'a fusestrip 25, and sheet 25 ot transparent insulating material such as micawhich is secured to one tace ot the insulating member.24, through which'the fuse strip 25 located upon the other side ot member 24 may beviewed. Yrlhis sheet ot mica forms an indicating means, the mica beingblackened by the blowing of the i'use, so that it can easily bedetermined7 without taking the plug out ot the socket or taking itapart, when the fuse has been blown. is the fuse and window are combinedin a unit-ary device, when `a new fuse is put in, a new window is alsoput in. rll`hus a clean window means that the fuse has not been blown,and a blackened window means that the -ituse has been blown. rllhe strip25 is composed ot any suitable fusible material and is pret;

erably widened at its ends, and those ends are bent over and around theinsulating member 24 as clearly indicated at 27 and 28. The ends ot thestrip thus engage the outer side of the transparent member 26. "When theIrenewable element B is placed in position -in the plug, the under sideof one' end of the strip 25 is firmly seated against the upper face ofthe-end 13 ofi the conducting strip 11.. ln this way ciruit is completedfrom the center contact 12 to one end ot the strip 25. ln order to bringthe end of the strip 25 into proper position to engage the end of theContact strip 11, the in sulating disk 24 ot the member B is providedwith a registering opening 29 and registering not-ches 30 and 31. 'lhesenotches and openings are fitted overy projections upon the upper end ofthe insulating plug body 10, the openinr 29 being fitted overprojections 32 and t e notches 30 and31 being fitted over projections 33and 34 respectively.

The shell member C includes a threaded shell 35, a cap 36 andintervening insulation 37. The shell 35 is composed of conductingmaterial and the threaded portion of the shell, designated 14, forms theshell contact of the plug.` The cap 36 which is preferably composed ofmetal is provided with a central aperture. A sheet of transparentinsulating material '38, preferably mica, is fitted into the end of-thecap and closes the aperture in the cap through which l may be sheet therei'iewable tuse element viewed. rEhe insulation 3T isin the 'torni ot aring which is forced against the disk 33 and lies between the outersurtace of the upper end oit the member 35 and the skirt or ot the capBtl. r The parts 3a, 36 and a! are first assembled wh: engaging portionsare cyl .drical i ll'lhen thus assembled thei7 are pressed out ordetormed at intervals to provide bumps7 39. By means oiI these bumpsthese j arts ot the shell member are held together. clearlyillustrated,the upper end ot the shell 35 is provided with inwardly extending flange40. the under side ot this flange` engages the end 27 of the Jfusestrip. This end, as previously noted, lies above the mica or othertransparent sheet 2G. Consequently an elec tric connection is providedwith the end of the `tuse strip 26 and the shell contact 14. rlhe pointat which the flange 4() engages the end ot' the -inse strip isdiametrically oppo site to that at which the other end ot the fuse stripengages the face 13 oi the center Contact strip 11. rl`hus oneconnection is made with the under side oli the tusible element l and theother connection is made with the upper side ot that element. s clearlyshown in 7, the shell 35 is cut away at 42 yso as to keep all portionsot' the shell 35 far enough away trom the end ot the strip 11 and theadj acentend of the Jfuse strip 25 to prevent a short circuit bet'weenthe center and shell contacts. noted that the cap 36 is separated fromthe end 28 ot the yfuse strip by means of 'the insulating sheet 38. i

rlhe shell member C is removably connected to the plug body A so thatthe two 4members may be separated in order to re place a used fusemember B. The connection between the members A and C is provided 'by aplurality ot spring strips 43 which extend into channels or grooves 44formed in the outer tace ot the wall 15 of the insulating member 10.These strips are preferably given the shape Iillustrated in Fig. 9.i Theupper end ot the shell 35 is struck up so as to provide `inwardlyexll-lhen the parts are assembled a llt will be 'tending projections 45which have substantially the same-cross section as the channels 44.These projections 45 it into the upper ends of the channels 44 and thuscenter the entire shell member C with reference to the plug member A.'Since these projections are struck up they provide depressions in theouter surfaces of the shell 35, and as cle-arly shown, the bottom ofeach of these depressions is open as indicated at 46. The spring strips43 extend through these open'- ings 46 and lie between the inner wall ofthe projection 45 and the insulation 37 as particularly illustrated inFig. 8. By constructing the strips 43 ot' spring metal the by the fusewhen the fuse is blown, so that the fuse and the transparent member canbe removed together and replaced by a new unitary device having a newfuse and an unblackened transparent element, said unitary renewabledevice being readily detachable as a unit from said plug, said unitarydevice being held in place on said plug by imeans` of said threadedshell Contact.

lln witness whereof, l have hereunto Subscribed my name.

REUBEN B. BlENqlAll/llll.

